The present invention relates to reinforcing concrete products. It is particularly applicable in reinforcing concrete pipe.
Concrete pipe is typically reinforced with welded wire fabric which is formed into a cylindrical configuration commonly referred to as "cage". The fabric itself comprises a first set of wire strands oriented generally parallel to one another and welded to a second set of generally parallel strands which are oriented transversely to the first set strands. In producing concrete pipe, such fabric is first formed into a generally cylindrical cage which is then inserted into a pipe making form.
Often, particularly in the case of larger pipe, the concrete pipe is reinforced with two cages, an inner cage and an outer cage. Special spacers comprising individual linking rods with some sort of hook at each end are provided to hold the two cages in spaced relationship with one another. Still other individual spacers have to be secured to at least the outer cage at various points to space the outer cage from the inner surface of the outside form wall which serves as a form for the concrete pipe. Where the pipe is formed by casting, both inner and outer pipe forms are provided and, often, the producer places special spacers on both the inside cage and the outside cage to space both cages from their adjacent inner and outer forms respectively.
Preparing a cage assembly in this way is a labor intensive operation. However, it is a job which has to be done and is one which has been done in the above manner for well over 25 years.